drop deprecated syntax for anonymous initializer blocks

compiler/testData/diagnostics/tests/secondaryConstructors/expectedInitKeywordOnInitializer.kt

@@ -1,10 +0,0 @@
-class A {
-    val x: Int
-    val y: Int
-    <!INIT_KEYWORD_BEFORE_CLASS_INITIALIZER_EXPECTED!>{<!>
-    x = 1
-    }
-    init {
-        y = 1
-    }
-}

compiler/testData/diagnostics/tests/secondaryConstructors/expectedInitKeywordOnInitializer.txt

@@ -1,10 +0,0 @@
-package
-
-internal final class A {
-    public constructor A()
-    internal final val x: kotlin.Int
-    internal final val y: kotlin.Int
-    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
-}